Author Topic: cabin fan system question (1988 pickup)  (Read 68 times)

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KauriJ

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cabin fan system question (1988 pickup)
« on: Jan 12, 2020, 01:03:28 PM »
Iím hoping someone here can point me in the right direction of how I can solve two (small) issues with the cabin fan system in my momís 1988 Toyota pickup.

When I turn the cabin fan on, leaves/fir needles/etc. come out of the air vents into the cabin. I had a similar problem with my 4Runner, and I ended up just needing to clean a mouse nest out of the blower fan. Iíve removed the leaf debris that was in the pickupís blower fan, but thereís still a lot (!) of stuff coming out of the air vents when I turn the fan on, especially when switched from recirculation to outside air.

Iím guessing all this debris is probably originating near the air intake, but I havenít found a diagram of where the air intake is for the cabin fan system, and if itís different than the air intake for the motor. (Incidentally, there was a small mouse nest beneath the engine air filter, so Iím thinking mice could be to blame for this issue.) I do have a copy of the book How to Keep Your Toyota Pickup Alive for the Compleat Idiot (which is appropriate for my skill level :) ) and the 1988 Toyota Truck and 4Runner Repair Manual, and itís possible that Iím just looking in the wrong places for info.

The second issue is that the lever for adjusting the temperature on the cabin fan/heating system seems to be jammed at about the midpoint, and thereís occasionally a rattling sound from that area when the truck is moving. (Hopefully not another mouse issue?) Would I be able to access this area if I take apart the dash, or is the box containing the controls for the fan system totally sealed?

Any advice regarding how to fix these issues will be greatly appreciated! (Including pointing me to a thread that I missed when searching on this topic :) ) Thank you!

KauriJ [OP]

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Re: cabin fan system question (1988 pickup)
« Reply #1 on: Jan 12, 2020, 08:55:47 PM »
I think I may have found the answer to my first questionÖ. If itís like the newer pickups then the air intake should be under the wiper tray/windshield cowl, so hopefully cleaning it out from there will make a difference.

arlindsay1992

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Re: cabin fan system question (1988 pickup)
« Reply #2 on: Jan 13, 2020, 03:42:30 AM »
To answer your first question, yes the intake is under the windshield cowl. Remove the wiper arms, then pop the hood to access three Phillips screws and two push pins that hold the cowl to the cab. There are big holes in the cab for air to flow in. Some trim levels have plastic screens that pop in to provide a rudimentary filter. If you're interested, I have a set. If your truck was originally equipped with A/C, the A/C evaporator in the dash is a big collector of debris since all HVAC air flows through that no matter what the temperature selection.

To access the controls you really need to remove the entire dash. Nothing is sealed, it can all be accessed and serviced, it's just a pain. I wouldn't be surprised if the heater valve under the hood is frozen or or stiff. This puts a large strain on the blue HVAC cable, which might have bent. Also, when stuff stiffens up, sometimes the HVAC control assembly simply cracks. So don't force the levers if they are stiff. A good teardown, clean, and lube can make all the HVAC move like butter and save precious parts from breaking.

KauriJ [OP]

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Re: cabin fan system question (1988 pickup)
« Reply #3 on: Jan 13, 2020, 02:02:06 PM »
Great, thank you for the detailed explanation! Iíll remove the windshield cowl as soon as I get a Phillips screwdriver with a short enough handle so itíll fit under the hood and I can take those three screws out. :) I donít know if it has a plastic screen, but Iíll check. And thereís no A/C.

Also, thank you for the advice about the heater valve and HVAC, and that I should not force the levers to move! Iíll try to take things apart and clean them, and see how far I get; if it turns out to be beyond my skill level Iíll bring it to a professional mechanic. Do you have any recommendations for minimizing the risk of breaking parts when taking apart the dash? I admittedly donít have a lot of practice with things like this but I hope to learn. :) Thanks!

 
 
 
 
 

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